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The development of the scanning tunneling microscopy has led to the development of related techniques which include the scanning near-field microscopy (SNOM) and the scanning thermal microscopy (SThM). These techniques provide sample information in addition to the simultaneously obtained topography. With SNOM normal optical microscopy contrast mechanisms (adsorbance, fluorescence, polarization, etc.) can be used. The principles and design of a SNOM are presented. Subwavelength resolution (better than λ/20) is demonstrated. In SThM, the contrast is provided by temperature and thermal conductivity. The design of a resistive thermal probe is described. Several operating modes are described and image contrast due to thermal conductivity is demonstrated.

Tuning forks as tip–sample distance detectors are a promising and versatile alternative to conventional cantilevers with optical beam deflection in noncontact atomic force microscopy (AFM). Both theory and experiments are presented to make a comparison between conventional and tuning-fork-based AFM. Measurements made on a Si(111) sample show that both techniques are capable of detecting monatomic steps. The measured step height of 0.33 nm is in agreement with the accepted value of 0.314 nm. According to a simple model, interaction forces of 30 pN are obtained for the tuning-fork-based setup, indicating that, at the proper experimental conditions, the sensitivity of such an instrument is competitive to conventional lever-based AFM.